# Identify this device, please **URL:** \ **Category:** Factual Questions\ **Created:** [November 6, 2021, 4:09am UTC](https://boards.straightdope.com/t/identify-this-device-please/953876 "2021-11-06T04:09:49Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Hatchie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hatchie/32/3983_2.png) [@Hatchie](https://boards.straightdope.com/u/Hatchie)\ **Post date:** [November 9, 2021, 6:20am UTC](https://boards.straightdope.com/t/identify-this-device-please/953876/21 "2021-11-09T06:20:43Z")
It might have been put there by a spy, they like to hide things in places no one would think to look. Come to think of it, what if that innocent-looking “Little Free Library” is really a drop for passing secret documents, and I happened to pick it up by mistake? Like Whittiker Chambers, except in that case it was a microfilm in a watermelon. I’m probaby not being cautious by posting this here, but do you supp ---
**Author:** ![pjd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pjd/32/3009_2.png) [@pjd](https://boards.straightdope.com/u/pjd)\ **Post date:** [November 9, 2021, 8:45pm UTC](https://boards.straightdope.com/t/identify-this-device-please/953876/22 "2021-11-09T20:45:21Z")
I see what you did there. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [November 10, 2021, 3:06am UTC](https://boards.straightdope.com/t/identify-this-device-please/953876/23 "2021-11-10T03:06:29Z")
> [@Hatchie](#): > > The English blurb says it was used for color mixing Ah, so its a metaphore for the trouble you go to while cooking. Making a large constant speed electric motor is a lot of trouble to go to to mix colours. (I think the reports get the intent wrong, the radial stripped disc was just a way to verify the speed at which it rotated. ) But anyway, its a lot of trouble to go to make a modern cooking “mixer”, but the intent is to to mix flavours rather than colours. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [November 10, 2021, 3:46am UTC](https://boards.straightdope.com/t/identify-this-device-please/953876/24 "2021-11-10T03:46:01Z")
My interpretation of colour mixing was that these are quantitative perceptual experiments, and are using colour wheels rotating at different speeds to measure the manner in which the eye perceives colour under specific circumstances. In particular it could be used to experiment with persistence effects, such as found with a [Newton Disk](https://en.wikipedia.org/wiki/Newton_disc). Here precise control of rotation speed would be required, so the machine would make sense. I very much doubt it has anything to do with mixing fluids. (I’m reasonably chuffed I got most of the machine right - it is a motor, and the centrifugal governor is what I though it was. The stack of pulleys make sense in order to allow a wider range of speeds, although there should be three pulleys on the side axle.) ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [November 10, 2021, 5:39am UTC](https://boards.straightdope.com/t/identify-this-device-please/953876/25 "2021-11-10T05:39:31Z")
The device is listed in the catalog under Hilfsapparate = “helper apparatus”. I think it is meant to connect to a variety of other contraptions in the catalog. The last sentence translates to: > The device is used for purposes where a very high level of accuracy is required, such as time sense experiments, with the tachistoscope and the like. It has low power and operates on little current. According to [Wikipedia](https://en.wikipedia.org/wiki/Tachistoscope): > A tachistoscope is a device that displays an image for a specific amount of time. It can be used to increase recognition speed, to show something too fast to be consciously recognized, or to test which elements of an image are memorable. [Previous page](https://boards.straightdope.com/t/identify-this-device-please/953876.md?page=1)